{"id":"CVE-2026-96027","kind":"vulnerability","aliases":["CVE-2026-96027"],"related":[],"title":"Windows Installer: use-after-free lets a local user gain higher privileges","description":"Use after free in Windows Installer allows an authorized attacker to elevate privileges locally.","summary":"A use-after-free bug in Windows Installer lets a local user who is already authorized on the machine raise their privileges. The sources give no further detail on the exact trigger or the affected Windows builds.","severity":"high","cvss":7.0,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","local-privilege-escalation","windows","windows-installer"],"not_affected_if":["no-local-untrusted-users","patched-nov-2026"],"how_to_check":"Check Windows Update history for the November 2026 cumulative update (released 2026-11-10); the KB and fixed build numbers for your Windows version are in the MSRC Security Update Guide entry for CVE-2026-96027 (not yet read).","fix":"Install the November 2026 (2026-11-10) Windows security update for your Windows version. Exact KB and build: unknown, look up on the MSRC page for CVE-2026-96027.","status":"open","published_at":"2026-11-10T19:21:59+00:00","first_seen_at":"2026-11-10T19:25:27+00:00","triaged_at":"2026-11-10T19:49:33+00:00","updated_at":"2026-11-10T20:06:00+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-10T19:49:33Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Windows Installer: use-after-free lets a local user gain higher privileges","impact":"high","summary":"A use-after-free bug in Windows Installer lets a local user who is already authorized on the machine raise their privileges. The sources give no further detail on the exact trigger or the affected Windows builds.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["windows","windows-installer"],"confidence":0.5,"fix_status":"unknown","needs_auth":"yes","worst_case":"local user gains elevated privileges on the Windows machine","analyst_note":"Find the Microsoft advisory for CVE-2026-96027 to confirm affected Windows builds and the patch KB.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-local-untrusted-users"],"who_is_affected":"Only machines running Windows with the Windows Installer component are in scope, and the attacker must already have a local account. The sources do not name the affected Windows builds or the exact trigger, so the team should check the vendor's advisory for the list.","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000662,"input_tokens":4474,"output_tokens":430,"severity_before":"high"},"analyst_status":"done","analyst_note":"Find the Microsoft advisory for CVE-2026-96027 to confirm affected Windows builds and the patch KB.","search":"'-2026':15A,18A '-96027':16A,19A 'affect':64B 'allow':73C 'alreadi':44B 'attack':76C 'author':45B,75C 'bug':34B 'build':66B 'cve':14A,17A 'detail':57B 'elev':78C 'escal':24B 'exact':60B 'free':6A,33B,69C 'gain':11A 'give':54B 'higher':12A 'infrastructur':20B 'instal':2A,28B,37B,72C 'let':7A,38B 'local':9A,22B,40B,80C 'local-privilege-escal':21B 'machin':48B 'privileg':13A,23B,51B,79C 'rais':49B 'sourc':53B 'trigger':61B 'use':4A,31B,67C 'use-after-fre':3A,30B 'user':10A,41B 'window':1A,25B,27B,36B,65B,71C 'windows-instal':26B","nicknames":[],"mitigations":[],"who_affected":"Only machines running Windows with the Windows Installer component are in scope, and the attacker must already have a local account. The sources do not name the affected Windows builds or the exact trigger, so the team should check the vendor's advisory for the list.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["high","infrastructure","localprivilegeescalation","windows","windowsinstaller"],"campaign_type":null,"search_a":"'-2026':15A,18A '-96027':16A,19A 'cve':14A,17A 'free':6A 'gain':11A 'higher':12A 'instal':2A 'let':7A 'local':9A 'privileg':13A 'use':4A 'use-after-fre':3A 'user':10A 'window':1A","search_b":"'affect':64B 'alreadi':44B 'author':45B 'bug':34B 'build':66B 'detail':57B 'escal':24B 'exact':60B 'free':33B 'give':54B 'infrastructur':20B 'instal':28B,37B 'let':38B 'local':22B,40B 'local-privilege-escal':21B 'machin':48B 'privileg':23B,51B 'rais':49B 'sourc':53B 'trigger':61B 'use':31B 'use-after-fre':30B 'user':41B 'window':25B,27B,36B,65B 'windows-instal':26B","search_c":"'allow':73C 'attack':76C 'author':75C 'elev':78C 'free':69C 'instal':72C 'local':80C 'privileg':79C 'use':67C 'window':71C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:21:59+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-96027","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-96027","severity":null,"published_at":"2026-11-10T19:21:59+00:00","modified_at":"2026-11-10T19:21:59+00:00","first_seen_at":"2026-11-10T19:25:27+00:00","fetched_at":"2026-11-10T19:25:27+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-96027:2607","url":"https://api.msrc.microsoft.com/cvrf/v3.0/updates/CVE-2026-96027","severity":null,"published_at":"2026-11-10T20:06:00+00:00","modified_at":"2026-11-10T20:06:00+00:00","first_seen_at":"2026-11-10T20:06:00+00:00","fetched_at":"2026-11-10T20:06:00+00:00","note":"MSRC CVRF API confirms the CVE is in the November 2026 Security Updates (released 2026-11-10). The MSRC advisory page and CVRF bulk document returned no content, so builds and KB numbers are not read. Nothing marked verified.","cites":["https://api.msrc.microsoft.com/cvrf/v3.0/updates/CVE-2026-96027"]}],"documents":[{"id":117775,"url":"https://api.msrc.microsoft.com/cvrf/v3.0/updates/CVE-2026-96027","title":"MSRC CVRF: CVE-2026-96027 in November 2026 Security Updates","kind":"advisory","source":"analyst","publisher":null,"text":"MSRC API lists CVE-2026-96027 under the November 2026 Security Updates, released 2026-11-10. No builds or KB in this response.","published_at":null,"relation":"advisory","confidence":null,"note":null}],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}